<p>In modern heavy vehicles low fuel consumption as well as good ride comfort and driveability is desired. Assuming that the road altitude ahead of the vehicle is known the optimal control regarding fuel and time consumption can be calculated. However this results in a bang-singular-bang control which decreases the ride comfort by introducing high jerk levels and oscillations in acceleration as well as jerk originating from the dynamics in the driveline.</p><p>In this thesis several methods to supress these behaviours are presented. A qualitative study of the methods impact on ride comfort as well as fuel and time consumption is carried out. A driveline model is implemented in Simulink and used for the evaluations. The aim is not to find a optimal strategy but rather to suggest methods and evaluate these as far as can be done in simulation to enable for future test runs.</p>

In modern heavy vehicles low fuel consumption as well as good ride comfort and driveability is desired. Assuming that the road altitude ahead of the vehicle is known the optimal control regarding fuel and time consumption can be calculated. However this results in a bang-singular-bang control which decreases the ride comfort by introducing high jerk levels and oscillations in acceleration as well as jerk originating from the dynamics in the driveline. In this thesis several methods to supress these behaviours are presented. A qualitative study of the methods impact on ride comfort as well as fuel and time consumption is carried out. A driveline model is implemented in Simulink and used for the evaluations. The aim is not to find a optimal strategy but rather to suggest methods and evaluate these as far as can be done in simulation to enable for future test runs.

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Thesis (MScEng (Mechanical and Mechatronic Engineering))--University of Stellenbosch, 2007. / Vehicles are expected to deliver adequate power for the engine size and vehicle class. They must also deliver good response to the driver’s desired action as well as deliver the lowest possible fuel consumption in all possible conditions and comply with emissions regulations. The combination of these factors is termed good driveability. Evaluating driveability is time and cost intensive and is most commonly evaluated from a subjective driver prospective. Advanced control systems allow for more accurate control of the vehicles response to the drivers demands. The objective of this document was to develop a quantitative driveability evaluation model for engine management calibration. The important aspects of engine management control for driveability, as well as how they are manipulated to deliver acceptable driveability were identified. Test procedures were developed to measure and quantify all these important factors. The test procedures can be evaluated for their different sections or for a complete driveability evaluation method. An optimised driveability evaluation method was developed to reduce the driveability evaluation time. Verification of the driveability evaluation model did provide different results for a different engine management calibration.

<p>A laser radar can be used to generate 3D data about the terrain in a very high resolution. The development of new support technologies to analyze these data is critical to the effective and efficient use of these data in decision support systems, due to the large amounts of data that are generated. Adequate technology in this regard is currently not available and development of new methods and algorithms to this end are important goals of this work.</p><p>A semi-qualitative data structure for terrain surface modelling has been developed. A categorization and triangulation process has also been developed to substitute the high resolution 3D model for this data structure. The qualitative part of the structure can be used for detection and recognition of terrain features. The quantitative part of the structure is, together with the qualitative part, used for visualization of the terrain surface. Substituting the 3D model for the semi-qualitative structures means that a data reduction is performed.</p><p>A number of algorithms for detection and recognition of different terrain objects have been developed. The algorithms use the qualitative part of the previously developed semi-qualitative data structure as input. The taken approach is based on matching of symbols and syntactic pattern recognition. Results regarding the accuracy of the implemented algorithms for detection and recognition of terrain objects are visualized.</p><p>A further important goal has been to develop a methodology for determining driveability using 3D-data and other geographic data. These data must be fused with vehicle data to determine the properties of the terrain context of our operations with respect to driveability. This fusion process is therefore called context fusion. The recognized terrain objects are used together with map data in this method. The uncertainty associated with the imprecision of the data has been taken into account as well.</p> / Report code: LiU-Tek-Lic-2008:29.

A laser radar can be used to generate 3D data about the terrain in a very high resolution. The development of new support technologies to analyze these data is critical to the effective and efficient use of these data in decision support systems, due to the large amounts of data that are generated. Adequate technology in this regard is currently not available and development of new methods and algorithms to this end are important goals of this work. A semi-qualitative data structure for terrain surface modelling has been developed. A categorization and triangulation process has also been developed to substitute the high resolution 3D model for this data structure. The qualitative part of the structure can be used for detection and recognition of terrain features. The quantitative part of the structure is, together with the qualitative part, used for visualization of the terrain surface. Substituting the 3D model for the semi-qualitative structures means that a data reduction is performed. A number of algorithms for detection and recognition of different terrain objects have been developed. The algorithms use the qualitative part of the previously developed semi-qualitative data structure as input. The taken approach is based on matching of symbols and syntactic pattern recognition. Results regarding the accuracy of the implemented algorithms for detection and recognition of terrain objects are visualized. A further important goal has been to develop a methodology for determining driveability using 3D-data and other geographic data. These data must be fused with vehicle data to determine the properties of the terrain context of our operations with respect to driveability. This fusion process is therefore called context fusion. The recognized terrain objects are used together with map data in this method. The uncertainty associated with the imprecision of the data has been taken into account as well. / <p>Report code: LiU-Tek-Lic-2008:29.</p>

This thesis work is based on a dynamic programming solution of a fuel optimizing cruise controller that was developed at Scania CV AB last year. Known data of the road ahead, mainly the slope, is used to continuously calculate the optimal torque and gear choices of a given moving vehicle for a certain horizon. The optimization calculations are based on fuel consumption and the vehicle's arrival time to the final destination. This report has been focused on achieving better "driveability" of the cruise controller while still maintaining the good fuel saving qualities that is already there. Simulation is used to evaluate the cruise controller on roads where the wanted data is known. The result is smaller speed variations on at road segments, which will improve a driver's impression of the cruise controller. The great fuel benefits of using roll-techniques in hilly areas is maintained from the previous implementation. The key to the optimal balance between these two behaviors is found using a method that limits the torque usage of the truck to a certain speed interval and then finds exception areas where the torque usage should be unlimited. / Detta examensarbete är baserad på en dynamisk programmeringslösning av en bränsleoptimerande farthållare som utvecklades på Scania CV AB förra året. Känd data om den framförvarande vägen, så som lutningen, används för att beräkna optimalt drivmoment och växelval för ett givet fordon för en viss horizont. Optimeringsberäkningarna baseras på bränsleförbrukning och fordonets ankomsttid till målet. Denna rapport focuserar på att uppnå bättre "körbarhet" för farthållaren och samtidigt behålla de goda bränslebesparande egenskaper som farthållaren redan har. Simulering nyttjas för att analysera farthållaren på vägar där önskad data är känd. Resultatet är mindre hastighetsvariationer på platta vägar, vilket bör förbättra förarens uppfattning av farthållaren. De stora fördelar som kommer med användning av rull-tekniker på kuperade vägsträckor bevaras från den tidigare implementeringen. Nyckeln till optimal balans mellan dessa två körbeteenden är en metod som går ut på att begränsa fordonets momentanvändning till ett visst hastighetsinterval och sedan hitta undantagsområden där momentanvändning borde vara obegränsad.

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